The long-term objective of this research are to learn more about the genetics and host preferences of the Ixodes tick vector of Lyme disease in the U.S., to determine if the Lyme disease spirochete Borrelia burgdorferi is present in the southeastern coastal states, and whether this disease may become a public health problem in this region of the future. These questions will be answer, at least in part, by (1) detailed investigations of the three U.S. Ixodes tick species known to be vectors of B. burgdorferi; (2) by extensive surveys of I. scapularis and (and I. dammini when collected) for presence of B. burgdorferi; and (3) screening of wild and domestic animal sera for presence of B burgdorferi antibodies. Specific aims are to (1) establish whether I. dammini (principal vector of Lyme disease in northeastern and northcentral U.S.), I. pacificus (vector in the pacific coastal area) and I scapularis (proven laboratory vector of B. burgdorferi from the southern U.S.) are reproductively isolated from each other; (2) evaluate the intra-and interspecific genetic variability of each species; (3) conduct comparative feeding experiments of immatures of the three Ixodes species on small mammals, birds and reptiles; (4) conduct host attraction experiments of these immature ticks to mammals birds and reptile; (5) continue quantitative ecological and bionomic studies of I. scapularis; (6) map the coastal north/south geographic distribution of I. scapularis and I dammini, and determine if I. dammini is extending its range southward; (7) initiate two types of surveys for presence of Lyme disease spirochetes, (a) a serological survey of selected deer, horses, dogs, small mammals, birds and lizards in the southeastern coastal states (particularly Georgia) and (b) a screening of suspect ticks for presence of B. burgdorferi. Descriptive and experimental approaches involving laboratory and field investigations will be employed. Techniques will involve interspecific hybridizations, chromosomal analyses (classical karyotypes and several banding techniques including fluorescent stains), electrophoretic isozyme analyzes, Ouchterlony double- diffusion procedures, western blotting, ELISA, fluorescent- antibody (FA) and indirect fluorescent antibody (IFA) techniques using monoclonial antibody to Borrelia burgdorferi.